Acumen, maybe? Acumen is more a description of natural ability, though, rather than a synonym for erudition (which is the accumulation of knowledge chiefly from books).
Acumen is synonymous with discernment, according to Merriam-Webster's online dictionary: "a power to see what is not evident to the average mind"
acquaintance
apprehension
acroama
awareness
apperception
assimilation
appreciation
Afraid is a synonym for scared. It begins with the letter a.
Learning
Satanic
Particle
agenda
Finish is another word for completion starting with the letter F.
used
another archive
recover
unclean :)
The word can be: Trailer or trolley.
throat
retreat
unkempt
littlest
pressed
stupendous